pollymc/java/javautils.cpp

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/* Copyright 2013 MultiMC Contributors
*
* Authors: Orochimarufan <orochimarufan.x3@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "multimc_pragma.h"
#include "classfile.h"
#include "javautils.h"
#include <QFile>
#include <quazipfile.h>
namespace javautils
{
QString GetMinecraftJarVersion(QString jarName)
{
QString version = MCVer_Unknown;
// check if minecraft.jar exists
QFile jar(jarName);
if (!jar.exists())
return version;
// open minecraft.jar
QuaZip zip(&jar);
if (!zip.open(QuaZip::mdUnzip))
return version;
// open Minecraft.class
zip.setCurrentFile("net/minecraft/client/Minecraft.class", QuaZip::csSensitive);
QuaZipFile Minecraft(&zip);
if (!Minecraft.open(QuaZipFile::ReadOnly))
return version;
// read Minecraft.class
qint64 size = Minecraft.size();
char *classfile = new char[size];
Minecraft.read(classfile, size);
// parse Minecraft.class
try {
char *temp = classfile;
java::classfile MinecraftClass(temp, size);
java::constant_pool constants = MinecraftClass.constants;
for(java::constant_pool::container_type::const_iterator iter=constants.begin();
iter != constants.end(); iter++)
{
const java::constant & constant = *iter;
if (constant.type != java::constant::j_string_data)
continue;
const std::string & str = constant.str_data;
if (str.compare(0, 20, "Minecraft Minecraft ") == 0)
{
version = str.substr(20).data();
break;
}
}
} catch(java::classfile_exception &) {}
// clean up
delete[] classfile;
Minecraft.close();
zip.close();
jar.close();
return version;
}
}